Automatic cable-clamping mechanism for cable-tool drill



. Dec. 23, 1958 A. c. HAISCH AUTOMATIC CABLE-CLAMPING MECHANISM FORCABLE-TOOL DRILL 4 Sheets-Sheet 1 Filed Feb. 13, 1956 ALBERT c. HAISCH,

INVENTOR,

BY ATTORNEY Dec. 23, 1958 A. c. HAISCH' 2,865,604

AUTOMATIC CABLE-CLAMPING MECHANISM FOR CABLE-TOOL DRILL Filed Feb. 1a,1956.

4 Sheets-Sheet 2 ALBERT c. HAlscH,

INVENTOR,

1 BY WAA Na 26 a ATTORNEY A. C. HAISCH AUTOMATIC CABLE-CLAMPINGMECHANISM FOR CABLE-TOOL DRILL Filed Feb. 13, 1956 4 Sheets-Sheet 3 a bm wv. M 2

4 a B Z u M@ x M. w B 0 m M w M. U 4 on u 0 T llllll 6 |l||l||l||l|||W-an 2 w w 7 FIG. 8.

ALBERT c. HAISCH,

INVENTOR BY 9k ATTORNEY Dec. 23, 1958 A. c. HAISCH 2,865,604

AUTOMATIC CABLE-CLAMPING MECHANISM FOR CABLE-TOOL DRILL Filed Feb. 13,1956 4 Sheets-Sheet 4 Fig. 9. 3!

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ALBERT C. HAISCH,

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'BYQJMAWMSW ATTORNEY 2,65,604 Patented Dec. 23, 1958 free AUTOMATICCABLE-CLAMPIN G MECHANISM FOR CABLE-TOOL DRILL Albert C. Haisch, SouthMilwaukee, Wis., assignor to Eneyrus-Erie Company, South Milwaukee,Wis., a cor poration of Delaware Application February 13, 1956, SerialNo. 565,145

7 Claims. (Cl. 255-11) This invention relates to new and usefulimprovements in a cable-clamping mechanism for spudder-type cabletooldrills.

Cable-tool drills as such, are well known in the art.

In such drills, a cable passes from a winch drum on.

the main frame, around a heel sheave at or near the pivot of a spuddingbeam, then under a spudding sheave at the oscillating end of thespudding beam, then over a crown sheave at the upper end of a mast andthen vertically downward into the hole which is being drilled in theground. Suspended at the lower end of this cable is a string ofpercussion drill tools, terminating in a bit. The spudding beam isoscillated by a pitman, actuated by a rotating crank. The oscillatingmotion of the spudding sheave of the spudding beam (hereinafter calledthe spudding-beam cycle) transmits vertical reciprocating drillingmotion to the drill tools (hereinafter called the drill-tool cycle).This motion is called spudding.

During drilling, the spudding-beam cycle is approximately 180 degreesout of phase with the drill-tool cycle, i. e., when the spudding beam isin its uppermost position the drill tools are at their lowest position,and vice versa. The cycle of the spudding beam starts from rest at itsupper position, accelerates downward reaching its maximum velocity atapproximately the midpoint of its downward stroke, decelerates theremainder of the downward stroke and comes to rest at its lowerposition. It then accelerates upward reaching its maximum velocity atapproximately the midpoint of its upward stroke, decelerates for theremainder of its upward stroke and comes to rest at its upper position.

If the rotating crank is operated slowly (i. e., at a speed such thatthe upward acceleration of the spudding sheave during the first half ofits upward movement is equal to or less than the downward accelerationunder gravity of the drill tools) the drill tools will follow a cycleexactly 180 degrees out of phase with the abovedescribed spudding-beamcycle, but at such speed the bit will not do useful Work because thedrill tools will be brought to rest by the spudding mechanism instead ofby impact at the bottom of the hole. If useful work is to be obtainedfrom the bit, it is necessary to operate the rotating crank at arelatively-high speed (i. e., at a speed such that (a) the upwardacceleration of the spudding sheave during the first half of its upwardmovement is greater than the downward acceleration under gravity of thedrill tools and (b) slack developed in the cable by the spudding sheaveovertravelling the drill tools, as a result to such difference in theirrespective accelerations, is sufficiently great that at least some ofsuch slack is maintained until an instant before drill-bit impact andreversal of the spudding sheave). When operated at such desired highspeed, the spudding-beam cycle will lead that of the drill tools and notretard them on their downward stroke. When operated in this manner, the

spudding beam begins tightening the cable (i. e., eliminating cableslack) an instant before bit impact at the bottom of the hole. Thus, thedrill cable is maintained taut during the upward stroke of the drilltools, in which they are accelerated to maximum upward velocity near themid;oint of the stroke and thereafter decelerated under influence ofgravity until they come to rest at the top of the stroke. Thereafter, asthe drill tools accelerate downward from the top of their stroke, thespudding beam accelerates upwardly but faster than the drill tools, thusallowing the drill tools to fall freely under gravity.

It is desirable, throughout the downward stroke of the drill tools, thatthey not be retarded by the spudding beam, and that they strike thebottom of the hole with maximum impact. To accomplish this, the spuddingbeam must initially overtravel the tools and accumulate sufficienLslackcable so that only in the final stages of spudding-beam decelerationwill the drill tools overtake the spudding beam and absorb the cableslack. Thus, during the downward stroke of the tools, the drill cable istaut at the beginning of the stroke, but accumulates slack during fallof the tools to approximately the midpoint of their downward stroke, atwhich point the cableslack diminishes, and the cable is finallytightened an instant before impact of the tools in the bottom of thehole.

This periodic slackening of the cable creates the following problem. Asslack cable accumulates, the slack extends to the winch drum causingcable coils on the drum to expand and loosen. An instant before thedrill tools reach the bottom of the hole, the slack cable is abruptlytightened. Repeated loosening and tightening of cable on the drumproduces wear on the drum surface and on the cable.

Various devices have been used in the past to clamp the cable at somepoint between the drum and the heel sheave in an attempt to keep thecoils of cable tight and in their proper position on the drum. In such adevice, the clamp is engaged at all times even if not needed. The clampthus serves no useful purpose while raising or lowering the drill tools.Furthermore the clamp and cable are subject to wear when the cableslides through the clamp, and on this account the clamp requiresfrequent adjustment.

Other devices have been used to hold the cable against the heel sheaveto resist accumulation of slack cable on the winch drum during spudding.These latter devices are usually provided with manual controls torelease the cable-holding means when not required. Such manual controlsrequire continuous attention of the operator.

Cable-tool drills have more recently generally been provided with anautomatic-feed mechanism, which automatically unspools cable from thedrum without interruption of spudding to supply the drill tools withadditional cable as the depth of the hole increases.

In such devices, automatic feeding occurs during that phase of thespudding cycle when cable tension is at a maximum, namely, at the timeof tool pick-up at or immediately following impact.

Accordingly, it is the principal object of the present invention toprovide a self-engaging and self-disengaging slack-holding devicesynchronized with the spudding mechanism which will overcome the aboveobjections.

A further object of this invention is to provide an automaticslack-holding device, which will be automatically engaged when cableslack normally occurs during spud ding, and which will be automaticallydisengaged when automatic feeding occurs during spudding and when toolsare raised and lowered by the winch.

In addition to the above-stated principal objects, a number of novel anduseful details have been worked out, which will be readily evident asthe description progresses.

The present invention consists in the novel parts and in the combinationand arrangement thereof, which are defined in the appended claims, ofwhich four embodiments are exemplified in the accompanying drawings,hereinafter particularly described and explained.

Throughout the description, the same reference number is applied to thesame member or to similar members.

Figure 1 is a side elevation of a spudder-type cable tool drillembodying one form of the present invention.

Figure 2 is a side elevation partly in section, of the first embodimentof the invention.

Figure 2A is an enlarged cross-section view of the brake, applicable toall embodiments of the invention, taken along lines 2A-2A of Figure 2.

Figure 3 is a plan view of the drive machinery of Figure 1 taken alonglines 33 of Figure 1.

Figure 4 is a side elevation, partly in section, of the secondembodiment of the invention.

Figure 4A is a section of Figure 4 showing a second variant of thesecond embodiment of the invention.

Figure 5 is a side elevation, partly in section, of the third embodimentof the invention.

Figure 6 is a side elevation, partly in section, of the fourthembodiment of the invention.

Figure 7 is a front elevation, partly in section, of the hydrauliccontrol valve of the second embodiment of the invention shown in itsbrake-setting position.

Figure 8 is a front elevation, partly in section, of the same valve asFigure 7 shown in its alternative brakeunsetting position.

Figure 9 is a schematic view showing the hydraulic circuits of thesecond embodiment of the invention.

Figure 10 is a schematic view showing the electrical circuits of thethird embodiment of the invention.

Figure ll is a schematic view showing the air circuits of the fourthembodiment of the invention.

Referring to Figures 1 and 3, a main frame 11, is I supported bycreeping traction 12.

Frame 11 supports a motor 14; a drive shaft 17 driven by the motorthrough belt 14a and associated pulleys;

a winch drum 16 drivable by drive shaft 17 through clutch 32, pinion 16aand gear 16b; and spudding gear 19 drivable by drive shaft 17 throughclutch 33 and pinion 18.

The winch 16 is controlled by means of a clutch 32, a conventional brake(not shown), and control levers (not shown). The spudding gear iscontrolled by means of a clutch 33 and control levers (not shown).

From winch 16, a cable 20 passes around heel sheave 21, rotatablymounted at the fulcrum end of spudding beam 23 on shaft 24, then underspudding sheave 22 rotatably mounted near the reciprocating end ofspudding beam 23, then over crown-sheave 25 supported at the top of mast13 by housing 25a, and then down to drill-string 15 terminating in a bit(not shown).

Crown-sheave 25 is mounted in a housing 25a, which is arranged in anyconvenient manner to slide up and down with respect to the mast 13. Thishousing 25a rests on alternately spaced steel and rubber discs 2511,which thus furnish a resilient support for crown-sheave 25. (See U. S.Patents No. 1,750,826, issued March 18, 1930, to George R. Watson, andNo. 2,587,638, issued March 4, 1952, to Johann H. Meier.) Thuscrownsheave 25, like sheave 22, constitutes a cable cooperating meansthat oscillates with the cable during the drilling cycle.

Pitman 28 is connected to spud-ding-gear 19 by crankpin 29 and tospudding beam 23 by pin 30. A cam 31 is keyed to shaft 27 for use withthe embodiments of Figures 4, 4A, 6, 7, 8, 9 and 11, hereinafterdescribed.

Power is transmitted from motor 14 to spudding beam 23 through the belt14a, drive shaft 17, clutch 33, spud:-

4 ding pinion 18, spudding gear 19, shaft 27, crank-pin 29, and pitman28.

The novel parts of the invention will now be de scribed.

Figures 2 and 2A show the first embodiment of this invention.

Heel sheave 21 is mounted for rotation and free lateral sliding on shaft24. Heel-sheave yoke 34 which consists of lateral spacers 34a andarcuate spacer plate 34b interconnecting side plates 34c and 34d oneither side of heel-sheave 21, is pivotally mounted on shaft 24 in aconventional manner to permit the yoke 34 to slide laterally on shaft 24and to permit shaft 24 to pivot relative to yoke 34 during spudding.Yoke 34 is held against rotation in either direction about shaft 24relative to frame 11 by transverse angle guides 11a and 11b which areattached to the frame 11 and engage and thereby restrict fore-and-aftmovement but permit lateral movement thereon of roller 26 mounted on thelower end of yoke 34. Inside heel-sheave yoke 34 is brake-shoe 35pivotally connected to said yoke 34 at its lower end by pin 40. Theinner portion of brakeshoe 35 (Figure 2A) covers a substantial part ofthe span of the brake-shoe arc, and hardened surface 36 on said portionopposes groove 21a of heel-sheave 21 for engagement with cable 20. Saidinner portion of brake-shoe 35 fits into cable-groove 21a in such amanner that when the brake is unset, clearance a between hardenedsurface 36 of brake-shoe 35 and cable 20 is less than clearances b and cbetween brake-shoe 35 and heel-sheave 21. Upon setting the brake, onlyhardened surface 36 engages cable 20 in cable-groove 21a of heel-sheave21.

Brake-shoe 35 could be constructed to engage with both heel-sheave 21and cable 20 in cable-groove 21a, but after wear on hardened surface 36,brake-shoe 35 would engage only heel-sheave 21, and cable 20 would thenslip through cable-groove 21a with resulting slack cable betweenheel-sheave 21 and winch 16.

In Figure 2, spring assembly 39, which includes spring housing 39a,compression spring 41, and axially adjustable seat 3915 for the innerend of spring 41, is mounted on the upper end of heel-sheave yoke 34.The outer end of spring 41 fits against shoulder 38, which is an upperextension of brake-shoe 35. At the upper end of brake-shoe 35, oppositeshoulder 38, is mounted roller 37. Mounted on spudding beam 23 near itsfulcrum is support 42 on which is mounted striking bar 43 which ispositioned to engage roller 37 when spudding beam 23 approaches itsupper position. When spudding beam 23 is in its lowered position, thebar 43 is disengaged from roller 37 so that the reaction of compressionspring 41 on shoulder 38 forces brake shoe 35 against cable 20 incable-groove 21a of heel-sheave 21 and clamps cable 20 between theheel-sheave 21 and brake shoe 35. As spudding beam 23 approaches itsupper position, striking bar 43 then contacts roller 37. Continuedrising of spudding beam 23 rotates brakeshoe 35 about pin 40 raisingbrake-shoe 35 off cake 20 and compresses spring 41 still further(position of brake shown in Figures 2 and 2A). As spudding beam 23lowers, bar 43 disengages roller 37 and brake-shoe 35 again contactscable 20 at surface 36 in cable-groove 21a of heel-sheave 21 andprevents slack cable from sliding therethrough.

During spudding, spudding beam 23 oscillates up and down, being pivotedon shaft 24 by crank-pin 29 and pitman 28 (Figure 1). When crank-pin 29is within a range of upper positions, predetermined by the position ofstriking bar 43 on the spudding beam, on either side ward-stroke (solidoutline in Figures 1 and-2),-ittends to pick up drill tools 15 beforethey reach theend of their downward stroke and impact at the-bottom ofthe hole. At the instant of impact,'whichoccurs an instant after cableslack has been taken up and the immediately subsequent reversal of thespudding sheave and pitman at the top of the spudding-beam cycle,considerable tension has developed in cable 20, depending on how fardrill tools 15 have had to overreach, thereby stretching the cable andcompressing the shock absorber 25b to strike the bottom of the hole andexpand their kinetic energy. The high load in cable, 20 at impactproduces a shock wave along the length of said cable causing thewinch-drum brake (not shown) to momentarily slip and feed off a lengthof cable 20. The amount of feed is dependent on the intensity of theshock wave and the setting of said winch-drum brake. Alternatively apositive automatic feed may be produced responsive to compression of theshock absorber 25b at impact of the drill bit, as shown and described indetail in U. S. Patent No. 2,587,638, to J. H. Meier.

As crank-pin 29 passes its top dead-center position, striking bar 43 andits support 42 move to the right, and spring 41 tends to reset thebrake. When crankpin 29 is approximately 40 degrees past top-dead centerposition, striking bar 43 on support 42 is disengaged from roller 37 andbrake-shoe 35 is fully set.

The above-described setting and nnsetting of the brake occurs with eachoscillation of the spudding beam. When clutch 33 (Figure 3) isdisengaged to stop spudding, the weight of drill-string 15 (Figure 1)will lift spudding beam 23 to its uppermost position. With the spuddingbeam in this position, brake-shoe 35 is unset, and winch 16 may beengaged to at will raise or lower the drill string. Once the weight ofdrill-string 15 is removed from cable 20, spudding beam 23 will fall toits lower position (dotted outline in Figures 1 and 2) under its ownweight, and brake-shoe 35 will again set to prevent slack line frombacking up and unwinding on winch 16.

Figures 2A, 4, 7, 8 and 9 show the second embodiment of this invention.Heel-sheave 34, roller 26, angle guides 11a and 11b, brake-shoe 35,hardened surface 36, cable 20, spudding beam 23, pitman 28, crank-pin 29and spudding gear 19, bear the same relationship to each other as theydid in the first embodiment.

A double-acting cylinder-piston assembly 44 is pinconnected toheel-sheave yoke 34 by pin 45. Piston rod 46 is pin-connected to thelive end of brake-shoe 35 by pin 47.

Cylinder 48 of said cylinder-piston assembly is connected into ahydraulic system for actuation of piston 79 in the following manner:

In Figure 9, a fluid sump 49 is connected by conduit 50 to fluid pump51, which supplies fluid under pressure to the system. A control valve53 (detailed in Figures 7 and 8) is mounted on the main frame 11 bybracket 52 secured by studs 54. The control valve 53 has a valve body 55with inlet port 56, upper and lower exhaust ports 57a and 57b, exhaustmanifold 57, and valve ports 58 and 59. Valve spool 60, having upper andlower annular rings 62 and 68, is fitted for longitudinal movementinside valve body 55. Spring 61 is seated at the upper end of valve body55 and biases valve-spool 613 downwardly in Figures 7 and 8.

In Figures 7 and 8, pump 51 is connected to valve inlet port 56 by fluidconduit 72. Fluid conduit 73 forms a fluid connection between valve port58 and cylinder port 71 (Figure 4) on one side of cylinder 48, and fluidconduit 74 forms a fluid connection between valve port 59 and cylinderport 76 (Figure 4) on the opposite side of cylinder 48. Fluid conduit 75connects exhaust manifold 57 and sump 49 (Figure 9). Relief Valve 77 isinterposed in fluid conduit 72 near pump 51.

One end of conduit 78 is connected to relief valve 77 and its other endis T-co-nnected to fluid conduit 75.

Valve rod 63 (Figures 7 and 8'), built integral with valve spool 60extends out of gland 64 of valve 53, and has cam follower 65 rotatablymounted on its end by yoke 66 and pin 67. Cam follower 65 rides on cam31. Cam 31 is keyed on shaft 27 and is synchronized with crank-pin 29(Figure 1) on spudding gear 19, so that the outer point on the camsurface 31 will reach topdead center the instant crank-pin 29 is attop-dead center. Accordingly, mention of top-dead center posi tion willhereinafter apply equally well to the position of both cam and crank.Top-dead center position, also will hereinafter correspond to thehighest point of oscillation of spudding beam 23 (solid outline, Figures1, 2, 4, 5, and 6).

Referring now to Figure 7, valve spring 61, retracted between the upperend of valve body 55 and the upper end of valve spool 60, normally holdssaid spool set in its lower position. In this position, upper annularring 62 of valve spool 60 directs pressure fluid entering at inlet port56 downward into valve port 59, while lower annular ring 68 of valvespool 60 blocks lower exhaust port 57b leading to exhaust manifold 57,and upper annular ring 62 directs exhaust fluid from the cylinderentering at valve port 58 into upper exhaust port 57a.

Upon rotation of cam 31 to within approximately 40 degrees of top-deadcenter (setting, Figure 8), the rise in pitch of cam 31 will shift valverod 63 and valve spool 60 upward, further compressing valve spring 61.With valve spool 61) in this position, its lower annular ring 68 directspressure fluid from inlet port 56 into cylinder port 58, while its upperannular ring 6 2 blocks upper exhaust port 57a leading to exhaustmanifold 57, and lower annular ring 68 directs exhaust fluid from thecylinder enterin at valve port 59 into exhaust port 5712.

After cam 31 rotates approximately 40 degrees past its top-dead centerposition, the drop in pitch of cam 31 allows cam follower 65 to fall,and valve spring 61 shifts valve spool 60 back to the position shown inFigure 7.

This second embodiment of the invention operates in the followingmanner.

If the spudding-mechanism is disengaged and drillstring 15 is suspendedon cable 20, the weight of said drill string will hold spudding beam 23in its uppermost position (Figure 1), and crank-pin 29 and cam 31 willbe at top-dead center position (Figure 8). Cam 31 then sets controlvalve 53 to interconnect fluid conduits 72 and '73, respectively, anddirect fluid under pressure from the pump to cylinder port 71 oncylinder 48 (Figure 4). Pressure fluid then forces piston 79 to the leftactuating piston-rod 46 to unset brake shoe 35.

At this setting of control valve 53, valve spool 66 directs exhaustfluid from cylinder port 76 on cylinder 48 through fluid conduits 74 and75 to the sump.

Spudding is started by engaging clutch 33 (Figure 3) causingcounterclockwise rotation of spudding gear 19,, crank-pin 29, and cam 31(Figure 1). After cam 31 rotates counterclockwise 40 degrees, camfollower 65 and valve spool 60 will shift under force of valve spring61, to the position shown in Figure 7. In this position, valve spool 61)connects fluid circuits 72 and 74, respectively, directing fluid underpressure from the pump to cylinder port 76 on cylinder 48 (Figure 4).Pressure fluid now forces piston 79 to the right actuating piston rod 46to set brake shoe 35 on cable 20 in cable-groove 21a during theremainder of pick-up of the drill string.

At the same time, valve spool 60 connects fluid conduits 72 and 75,permitting fluid to exhaust from cylinder 48 through cylinder port 71 tothe sump.

Brake shoe 35 remains set until cam 31 thenadvances to withinapproximately 40 degrees of top-dead center position. At this point, camfollower 65 moves upwardly under .force ofcam 31, and valve spool 66 isshifted 7 to the brake unsetting position (Figure 8), previouslydescribed.

Thus, the brake is automatically set and unset, responsive to thespudding mechanism during the drilling cycle. The brake is unset duringthe lower stage of fall of the bit and the initial stage of raise of thebit. It is during this period of the spudding cycle that cable isautomatically fed to the drill string. The brake remains set at allother times during the spudding cycle.

A second variant of this embodiment is shown in Fig ure 4A.

The structure of this variant is the same as shown in Figures 4, 7, 8and 9 previously described, except that cylinder-piston assembly 44a issingle-acting instead of double-acting, and fluid conduit 74 is nowconnected to sump 49 rather than to the left end of the cylinder.

Spring-assembly 69, fitted over piston rod 461:, is retracted betweenthe end of cylinder-piston assembly 44a and nut 70 threaded on the outerend of piston rod 465:. The force of spring-assembly 69 normally setsbrake shoe 35 on cable in cable-groove 21a of heel-sheave 21.

Accordingly when valve spool 60 is in the lowered position (Figure 7),fluid from pump 51 and fluid conduit 72 will be directed back to thesump through valve body 55, exhaust manifold 57, and fluid conduit 74(now connected to the sump). Fluid exhausted from cylinder 48a (Figure4A) through cylinder port 71 will flow to the sump by way of fluidconduit 73, valve body 55, exhaust manifold 57 and fluid conduit 75.Spring assembly 69 holds brake shoe set.

When valve-spool is shifted to its upper position (Figure 8) by cam 31,fluid will flow from pump 51, through fluid conduit 72, valve body 55,fluid conduit 73, cylinder port 71 (Figure 4A), and into cylinder 48a toforce piston 79 and piston rod 46a to the left unsetting brake shoe 35.No fluid will be exhausted from cylinder 48a at this setting, therefore,fluid conduits 74 and 75 (which now lead to the sump), areinterconnected by valve spool 60.

The third embodiment of this invention is shown in Figures 5, 2A and 10.

In this embodiment, brake shoe 35, hardened surface 36, cable 20,spudding beam 23, pitman 28, crank-pin 29 and spudding gear 19 bear thesame relationship to each other, as they did in the first embodiment.

In Figure 5, heel-sheave yoke 93 is supported to slide axially on shaft24, the same as brake housing 34 described under the first embodiment.Electric solenoid is pivotally connected at one end to heel-sheave yoke93 at hanger 81 by pin 82, and at its other end to brake lever-arm 83 bypin 84. contactor support 85, which is an L-shaped piece of springsteel, is fastened to heelsheave yoke 93 near solenoid 80. Contactorsupport 85 has an electrical contactor 86 fastened to its lower end andwire 87, attached to electrical contactor 86, extends along contactorsupport 85 to a connection on terminal post 88. Terminal post 88 iselectrically connected to one side of solenoid 80 by wire 89. The otherside of solenoid 80 is electrically connected to one side of generator90 (Figure 10) by wire 91. The other side of generator 90 iselectrically connected to a cooperating electrical contactor 92 by wire97. Contactor 92 is attached to support 42 mounted on spudding beam 23,and is engageable with electrical contactor 86.

Thus electrical contactors 86 and 92 comprise an electrical switch forclosing the circuit to solenoid 89.

Spring assembly 39 is mounted on heel-sheave yoke 93 (Figure 5). Spring41 is compressed against brake-shoe 35 to normally hold the brake set oncable 29 in cable groove 21a of heel-sheave 21.

After spudding beam 23 pivots upwardly to a point where crank-pin 29 isapproximately 40 degrees from top-dead center (Figure 1), electricalcontactor 92 (Figure 5) carried by spudding beam 23 engages electricalcontactor 86, closing the switch and the circuit to solenoid 80.Solenoid 80, thus electrically energized, retracts and unsets brake shoe35. As spudding beam 23 continues to pivot upwardly, contactor support85 will bend to the left, and maintain switch 86-92 closed.

When crank-pin 29 passes top-dead center, spudding beam 32 andelectrical contactor 92 reverse direction. The spring of contactorsupport 85 will hold switch 86-92 closed until crank-pin 29 isapproximately 40 degrees past top-dead center, whereupon electricalcontactors 86 and 92 separate to open the switch and deenergize solenoid80. Spring assembly 39 then resets the brake.

Once spudding has stopped and drill-string 15 is suspended on cable 20,spudding beam 23 will automatically pivot to its uppermost positionunder the weight of the drill string, and switch 86--92 will close.Thus, the brake is unset to allow unrestricted use of winch 16.

The fourth embodiment of this invention is shown in Figures 6, 2A and11.

Here again, heel-sheave yoke 34, brake shoe 35, roller 26, angle guides11a and 11b, hardened surface 36, cable 20, spudding beam 23, pitman 28,crank-pin 29, and spudding gear 19 bear the same relationship to eachother as they did in the first embodiment.

In Figure 6, a conventional single-acting vacuum-actuated diaphragm 94is mounted on top of heel-sheave yoke 34. Plunger-rod 95 ispin-connected by pin 98 to link 96 bolted on the live end of brake-shoe35. A flexible conduit 99 is connected to diaphragm 94 at port 100.

Spring assembly 39 functions in the same manner for normally holding thebrake set on cable 20 in cable groove 21a of heel-sheave 21, aspreviously described for the first and third embodiments.

Turning to Figure 11, vacuum pump 10]. has an airtight connection withvacuum tank 162 through conduit 103. A conventional two-way valve 107 ismounted on main frame 11 near the end of shaft 27. Cam 31 is keyed tothe end of shaft 27, as previously described for the second embodiment.Cam arm 104 is pivoted at one end on frame 11 by pin 105. Cam follower65, which rides on cam 31, is pivoted on the other end of cam arm 104 bypin 109. Valve rod 106 of valve 107 is pinconnected to earn arm 104.

Conduit 108 interconnects vacuum tank 102 and valve 107, and conduit 99interconnects valve 107 and diaphragm 94. Valve 107 is spring loaded tonormally close off conduit 168 and vent conduit 99 to the atmosphere,whenever cam follower 65 rides the depressed surface on cam 31. Thiscondition occurs between approximately 40 degrees past and approximately40 degrees before top-dead center position of cam 31. When cam 31 iswithin 40 degrees of its top-dead center position, cam follower 65 risesand pivots cam arm 194 counterclockwise about pin 195, shifting valve107 to interconnect conduits 108 and 99. Diaphragm 94 is thenvacuum-actuated to retract, thereby shifting its plunger rod 95 to theleft unsetting the brake.

When spudding is stopped, the weight of the drill string rotatescrank-pin 29 and cam 31 to their top-dead center position. Thus, cam 31shifts valve 107 to its other position, and diaphragm 94 unsets thebrake. Winch 16 may then be operated to raise or lower the drill string.

This fourth embodiment need not be limited to a vacuum system, but acompressed air system is readily adaptable to the embodiment byreplacing the vacuum pump and air diaphragm with equivalent airequipment, such as an air' compressor and air motor, respectively.

It will be noted that in all embodiments of this invention the sheave 21and its cooperating brake 35 constitute in effect a cable-clamping meansfor clamping the cable 20 in fixed relation to the drill frame 11, saidcableclamping means being actuable to so clamp the cable in response topredetermined positioning of the spudding means 19, 22--24, 27-30; andthat accordingly the cable clamping means could if desired be located onother parts of the drill frame than the heel of the spudding beam, thelatter arrangement being merely a convenient location in the preferredconstruction, and other forms of rotatable or nonrotatablecable-receiving or cableengaging devices could be substituted for thesheave 21 to cooperate with the braking elements of the cableclampingmeans.

It will further be noted that the cable-clamping means is actuated tounclamp the cable during a predetermined portion of the drilling cycleresponsive to oscillation of cable-cooperating means, such as thespudding means, which oscillates with the cable during the drillingcycle; and that although this response is preferably achieved byactuating the clamping means responsive to cyclical positioning of thespudding means, the same result can be achieved by actuation responsiveto cyclical positioning of any other element that cooperates with thecable to oscillate therewith in the same or in a related cycle, such as,for example the yieldably-mounted oscillating sheave 25.

It can be readily seen that the above-described four embodiments providesimple and efficient automatic means for holding the drill cable tautduring spudding and prevent it from loosening and tightening on theWinch drum,

but will: (1) Release the cable for automatic feed to the drill stringduring each spudding cycle, just prior to bottoming the bit in the drillhole, and (2) Release the cable when spudding is stopped to allow thewinch to operate efliciently and freely.

Throughout the description of the four embodiments of this invention,the angular displacement of the crank and, in the second and fourthembodiments, the cam is designated as 40 degrees before their top-deadcenter posi tion to 40 degrees past their top-dead center position,during which time the brake is unset. Let it be understood, that thisangular displacement may be varied, with varied results in brake settingand unsetting, by making one or more of the following adjustments: (1)In the bracket on the spudding beam (first and third embodiments), (2)In the crank and pitman (all embodiments), (3) In variation of the Widthof the rise of the cam (second and fourth embodiments) and (4) In thesynchronization of crank and cam (second and fourth embodiments).

The first embodiment is the preferred showing of this invention, becauseof its simplicity and ease of adjustment; however, all five forms ofthis invention will operate efliciently.

Having now described and illustrated five forms of the invention, it isto be understood that the invention is not to be limited to the specificforms or arrangement of parts herein described and shown.

What is claimed is:

1. In an automatic cable-clamping mechanism for a cable-tool drillhaving: a drill frame; a cable; a winch operatively connected to thecable for winding in or paying out the cable; a drill bit suspended bythe cable; and spudding means for imparting vertical reciprocatingmotion to the cable including a spudding beam pivotally mounted on theframe, a heel sheave about which the cable is reeved pivotally mountedadjacent the pivot of the spudding beam, a spudding sheave about whichthe cable is reeved and rotatably mounted on the spudding beam andspaced from said pivot, and drive means operatively connected to thespudding beam for reciprocating the spudding beam; the combinationtherewith of: a brake supported by the drill frame adjacent the heelsheave and engageable with the cable for braking said heel sheave andcable; brake-setting means connected to the brake and the frame fornormally setting the brake; and means actuated in response to positionof the spudding means for automatically unsetting the brake when thespudding beam reaches a position in advance of its normal reversalposition from a bit-lowering to a bitraising stroke and thereafterholding said brake unset during a predetermined portion of its cycle.

2. An automatic cable-clamping mechanism for a cabletool drill accordingto claim 1, further characterized by the fact that the means toautomatically unset the brake includes a reciprocating element supportedby and reciprocable with the spudding beam and positioned thereon toengage the brake to unset the brake when the spudding beam reaches itsadvance position.

3. An automatic cable-clamping mechanism for a cabletool drill accordingto claim 1, further characterized by the fact that the means toautomatically unset the brake includes: a fluid motor connected betweenthe drill frame and the brake, and fluid control means for said motor;said fluid control means including a fluid-control circuit, areciprocating cam actuated by the spudding means, and a control valve insaid circuit actuated by said cam.

4. An automatic cable-clamping mechanism for a cabletool drill accordingto claim 3, further characterized by the fact that the fluid motor is ahydraulic pressureactuated ram.

5. An automatic cable-clamping mechanism for a cabletool drill accordingto claim 3, further characterized by the fact that the fluid motor is apneumatic vacuumactuated air-diaphragm type ram.

6. An automatic cable-clamping mechanism for a cabletool drill accordingto claim 1, further characterized by the fact that the means toautomatically unset the brake includes: an electric motor connectedbetween the drill frame and the brake, and control means for said motor;said control means including an electric circuit and a switch in saidcircuit actuated by said spudding means.

7. In an automatic cable-clamping mechanism for a cable tool drill, thecombination of: a drill frame; a vertically reciprocable drill toolcable; a winch for winding in and paying out the cable; reciprocatingcable-actuating means for imparting vertical reciprocating motion to aportion of the cable; a cable-clamping brake supported by the drillframe and engageable with the cable for braking a second portion of saidcable, intermediate the winch and the reciprocated portion of the cable,against motion relative to the drill frame; brake-setting meansconnected to the brake and the frame for normally setting the brake; andmeans actuated in response to position of the cableactuating means forautomatically unsetting the brake when the cable-actuating means reachesa position in advance of its normal reversal position from atool-lowering to a tool-raising stroke and thereafter holding said brakeunset during a predetermined portion of its cycle.

References Cited in the file of this patent UNITED STATES PATENTS

